Abstract: To reveal its influence on quasicrystal structure analysis, multiple diffraction (MD) effects in a basic Co-rich decagonal Al-Co-Ni quasicrystal have been investigated in-house and with synchrotron radiation. Two weak reflections were chosen as the main reflections (P) in the in-house measurements and 40° ψ-scans of one main reflection have been performed with synchrotron radiation. As well known for periodic crystals and the i-quasicrystal, it is also observed for this d-quasicrystal that the intensity of the main reflection may significantly increase if the simultaneous (H) and the coupling (P-H) reflections are both strong. The occurrence of MD events during collection of a full data set as well as the ψ-scans measurements have been studied based on an average structure model and the kinematical MD theory.

Abstract: The tracer diffusion of aluminium in the CuCr1Zr alloy was investigated, a material widely employed as an electrode in resistance spot welding. As a tracer layer, an alloy of Cu – 8.8 at.% Al was used, which was deposited by ion-beam sputtering. Isothermal diffusion annealing experiments were carried out between 500 and 700 °C, at temperatures relevant for industrial welding conditions. Al depth profile analysis was done by Secondary Ion Mass Spectrometry. The results revealed that aluminium exhibits a temperature-dependent diffusion behaviour. The diffusivities can be fitted together with literature data on Al diffusion in pure Cu obtained at higher temperatures according to the Arrhenius law. An activation enthalpy of 2 eV is obtained. The influence of a surficial oxide layer on the diffusion process is discussed.

Abstract: This study presents the first metallurgical analysis of twenty-five votive statuettes of Hercules from the National Archaeological Museum of Campobasso, Molise, Italy. These artifacts, which have previously been unexamined from a metallurgical perspective in the region, were analyzed to understand their composition, manufacturing techniques, and current state of preservation. All the samples were first analyzed in situ using X-ray fluorescence (XRF) and then were sampled to conduct microstructural analyses on polished cross-sections by optical and scanning electron microscopy. The statuettes revealed a ternary Cu-Sn-Pb alloy, consistent with historical alloying practices and manufacturing techniques typical of the period. The study highlights a homogeneous biphasic microstructure with dispersed lead nodules within the bronze matrix. The corrosion products on the surface have peculiar colors and textures due to both the finishing process and the alteration accord over centuries of abandonment, aiding the understanding of the material's behavior over time. The compositional results confirm the usage of materials and techniques in line with other coeval artifacts. Additionally, corrosion studies using Raman spectroscopy and the reproduction of the statuettes through casting will be conducted to develop a conservation protocol, to create inclusive displays for museum audiences.

Abstract: The paper presents the detailed comparisons of solute macro-segregation pictures predicted by different meso-macroscopic simulations, based on the single domain enthalpy-porosity approach coupled with distinct models of flow resistance in the two-phase zone. In the first, the whole zone is treated as a Darcy's porous medium (EP model); in the other two, the columnar and equiaxed grain structures are distinguished using either the coherency point (EP-CP model) approach or by tracking a virtual surface of columnar dendrite tips (EP-FT model). The simplified 2D model of a solidifying cast in a centrifuge is proposed, and calculations are performed for the Pb-48%wt Sn cast at various hyper-gravity levels and rotation angles. It is shown that the predicted macro-segregation strongly depends on the mesoscopic model used, and the EP-FT simulation (validated with the AFRODITE benchmark) provides the most realistic solute inhomogeneity pictures. The EP-FT model is further used to investigate the impact of the hyper-gravity level and the cooling direction on the compositional nonuniformity developing in centrifuge casting. The hyper-gravity level visibly impacts the macrosegregation extent. The region of almost uniform solute distribution in the slurry zone rises with the increased effective gravity, though the solute channeling is more severe for higher gravity and rotation angles. A-channeling and V-channeling were observed for angles between the gravity vector and cooling direction lower than 120° and higher than 120°, respectively.

Abstract: This work examines how rolling speed, feeding rate, and pass schedule—with a constant total reduction—affect the stress–strain fields, rolling force, and texture evolution of Al–Cu–Sc alloy sheets. A coupled finite element (FEM) and viscoplastic self-consistent (VPSC) framework is employed and compared with EBSD measurements to connect macroscopic fields with microscale texture changes. Results indicate that increasing rolling speed raises the effective strain rate and deformation heating, which lowers peak rolling force and improves in-plane stress homogenization on the RD–ND plane, while enhancing surface–core incompatibility and residual-stress gradients along the ND–TD direction. A higher feeding rate mainly intensifies work hardening, slightly elevates rolling force, and promotes near-surface stress/strain localization; in contrast, multi-pass schedules redistribute deformation between passes and reduce macroscopic stress concentration. Texture analyses show a speed-induced rotation from 〈001〉 toward 〈111〉 orientations, strengthening shear-related components; KAM maps suggest increased local orientation gradients consistent with higher stored energy. The simulations capture the principal experimental trends across conditions, supporting the use of the combined framework for trend-level process guidance. Overall, the findings clarify parameter–microstructure relationships and provide a basis for designing rolling routes that balance force reduction, stress uniformity, and texture control in Al–Cu–Sc sheets.

Abstract:

The adoption of advanced high-strength steels (AHSS) in the automotive industry have significantly increased in recent years driven by weight reduction and enhanced crashworthiness. Hot dip galvanised sacrificial coatings are regularly applied to these steels for corrosion protection. In this investigation, the scanning vibrating electrode technique (SVET) demonstrated that hydrogen evolution on the steel substrate is taking place when these sacrificial coatings are damaged during service, increasing the risk of hydrogen embrittlement. The hydrogen embrittlement susceptibility of a new generation of nano-precipitate ferritic, FNP, AHSS have been studied and compared against conventional dual phase ferritic-martensitic, FM, AHSS at equivalent strength levels. Hydrogen permeation tests have shown that FNP AHSS have lower effective diffusion coefficients, Deff, than FM AHSS at equivalent strength levels. At 800 MPa strength level D_eff were 1.68×10^-7 cm²/s and 1.87×10^-7 cm²/s for FNP800 and FM800 respectively. At higher strength levels, 1000 MPa, D_eff were 7.45×10^-8 cm²/s and 1.45×10^-7 cm²/s for the FNP1000 and FM1000, respectively. Slow strain rate tests (SSRT) showed that FNP AHSS displayed over 35% higher resistance to hydrogen embrittlement than conventional FM AHSS. Quantitative fractographic analyses confirmed that the new ferritic nano-precipitate microstructure retains much more ductile behaviour than conventional martensitic-ferritic even under the most severe hydrogen charging conditions tested.

Abstract: This study investigates the effects of Ti addition on the microstructures, melting temperature ranges, thermal expansion behavior, high temperature creep and oxidation resistances of an equimolar CoNiFeCr alloy of a foundry origin. 1.5 wt.% Ti added did not really change the single–phased state of the reference quaternary alloy but induces a significant decrease of the melting start and melting end temperatures. The thermal expansion coefficient is slightly lowered only while the creep resistance at 1100°C is significantly enhanced. The oxidation at 1200°C is controlled by species diffusion through a continuous chromia layer and the parabolic constant is higher than for the quaternary alloy, due to external and internal Ti oxidation. The presence of a thin layer of titanium oxide covering the chromia scale is suspected to limit chromia volatilization and scale spallation at cooling. Globally Ti demonstrated a globally beneficial influence of the high temperature properties of the alloy.

Abstract: The transition from regular to anomalous eutectic structures critically impacts the mechanical properties of eutectic alloys. This study investigated the non-equilibrium solidification behavior of Ni-Sn alloys using Bridgman directional solidification coupled with Cellular Automaton (CA) simulations. Unlike deep undercooling methods, this approach can offer a solution by decoupling temperature gradient and growth velocity during the solidification process, revealing that anomalous eutectic formation occurs specifically at growth velocity transition zones, not during steady-state growth (0.1–2000 μm/s). CA simulations confirmed that velocity jumps destabilize regular lamellae, the Ni3Sn phase epitaxially grows along the substrate in a cellular manner, triggering independent α-Ni nucleation followed by Ni₃Sn encapsulation. This work identifies a distinct process window for anomalous eutectic formation and elucidates its decoupled nucleation mechanism, advancing non-equilibrium solidification theory.

Abstract: In the production of stainless steel, chromium losses, particularly in the Electric Arc Furnace (EAF) phase, pose a challenge. This study addresses these issues by reviewing and analyzing the thermodynamics of the Fe-Cr-C-O system, highlighting discrepancies in existing literature regarding Gibbs free energies, interaction parameters, and other thermodynamic data. We developed a simple to use thermodynamic model to simulate the oxidation process using established data from scientific literature. The model calculates the equilibrium solubilities of chromium and carbon, showing how process variables like temperature, partial pressure of carbon monoxide, and silicon concentration influence chromium oxidation. The findings confirm that higher temperatures and the presence of silicon significantly reduce chromium loss by favoring carbon oxidation over chromium. The research concludes by providing practical guidelines for minimizing chromium losses in EAFs, such as protecting scrap with carbon, silicon, and aluminum; controlling oxygen intake; and ensuring a high melt temperature during decarburization. These guidelines aim to improve the economic efficiency and sustainability of stainless steel production.

Abstract: Top-bottom combined blowing converter steelmaking involves complex thermodynamic and kinetic processes.The development and application of predictive models for the converter smelting process have long been a focal point in steelmaking research.This paper establishes a kinetic process prediction model for converter steelmaking that can provide on-site guidance. Initially,based on actual production data and real field conditions from a specific company, machine learning models—including BP neural networks,random forests,and XGBoost—are coupled to predict the Tapping Steel Oxygen (TSO) composition for each heat in the production process.The prediction results serve as inputs for the kinetic model.Subsequently,existing kinetic models are analyzed,and an optimized theoretical kinetic model for the converter steelmaking process is selected.The accuracy of this kinetic model is evaluated using measured Tapping Steel Carbon (TSC) data.Finally,a data cyclic iteration algorithm is employed to integrate converter control parameters into the theoretical model of decarburization kinetics.By comparing the prediction accuracy of the decarburization kinetic model before and after incorporating control parameters,the effectiveness of integrating control parameters into the theoretical model is validated.Evaluation results of the decarburization kinetic model’s prediction accuracy show that,after incorporating control parameters,the prediction accuracy of TSC carbon content within the range [-0.2, +0.2] improved by 6.26%.This study provides a new approach for optimizing converter kinetic process prediction models and offers significant guidance for real-time monitoring and adjustment in production practice.

Abstract: The development of efficient and sustainable hydrogen storage materials is a key challenge for realizing hydrogen as a clean and flexible energy carrier. Among various options, metal hydrides offer high volumetric storage density and operational safety, yet their application is limited by thermodynamic, kinetic, and compositional constraints. In this work, we investigate the potential of machine learning (ML) to predict key thermodynamic properties—equilibrium plateau pressure, enthalpy, and entropy of hydride formation—based solely on alloy composition using Magpie-generated descriptors. We significantly expand an existing experimental dataset from ~400 to 806 entries and assess the impact of dataset size and data augmentation, using the PADRE algorithm, on model performance. Models including Support Vector Machines and Gradient Boosted Random Forests were trained and optimized via grid search and cross-validation. Results show a marked improvement in predictive accuracy with increased dataset size, while data augmentation benefits are limited to smaller datasets and do not improve accuracy in underrepresented pressure regimes. Furthermore, clustering and cross-validation analyses highlight the limited generalizability of models across different material classes, though high accuracy is achieved when training and testing within a single hydride family (e.g., AB2). The study demonstrates the viability and limitations of ML for accelerating hydride discovery, emphasizing the importance of dataset diversity and representation for robust property prediction.

Abstract: This study presents a carbon footprint assessment of a novel electroslag method for cadmium (Cd) recovery from spent nickel-cadmium (Ni-Cd) batteries. The process utilizes molten KCl–NaCl flux and carbon as a reductant under electrovortex flow stirring. Energy inputs and CO₂ emissions are calculated for active process stages and compared to conventional methods. Updated analysis excludes flux melting, recognizing the flux as a non-consumable transport and protection medium. The results highlight the method’s potential for sustainable, continuous cadmium recovery.

Abstract: The Bi-Sn, Bi-Sn-Ag, and Bi-Sn-Sb solder alloy systems represent lead-free, environmentally friendly alternatives for reliable electronic assembly. These alloys comply with increasingly strict environmental and health regulations, while offering low melting points suitable for soldering temperature-sensitive components. The addition of Ag or Sb improves mechanical strength, hardness, wear resistance, and thermal stability. Microstructural analysis confirmed homogeneous, defect-free surfaces. Comprehensive microstructural characterization using optical microscopy, SEM, EDS, and BSE imaging revealed refined, heterogeneous microstructures with distinct phase segregation. Dendritic growth, eutectic formations, and intermetallic compounds were observed. Sb addition promoted granular intermetallics, while Ag induced needle-like precipitates along phase boundaries. EDS confirmed expected compositions, and BSE imaging enhanced contrast between Bi-, Sn-, Sb-, and Ag-rich regions. The study also reports the thermal and electrical conductivities of Bi60Sn40, Bi60Sn35Ag5, and Bi60Sn35Sb5 alloys over the 25–140 °C range. Bi60Sn40 showed an increase in thermal conductivity from 16.93 to 26.93 W/m·K, while Bi60Sn35Ag5 reached 18.28 W/m·K at 25 °C, and Bi60Sn35Sb5 exhibited 13.89 W/m·K. These findings underline the critical influence of alloying elements on microstructure, phase stability, and thermophysical behavior, supporting their application in low-temperature soldering technologies.

Abstract: To address the central cracking problem in continuous casting slabs of 38CrMoAl steel, high-temperature tensile tests were performed using a Gleeble-3800 thermal simulator to characterize the hot ductility of the steel within 600 – 1200 °C. Phase transformation behavior was computationally analyzed via Thermo-Calc software, while microstructure, fracture morphology, and precipitate characteristics were systematically investigated using metallographic microscope(MM), field emission scanning electron microscope(FE-SEM), and transmission electron microscopy(TEM). Additionally, the effects of different holding times and cooling rates on the microstructure and precipitates of 38CrMoAl steel were also studied. The results show that the third brittle temperature range of 38CrMoAl steel is 645 – 1009 °C, and the fracture mechanisms can be classified into three types: (I) In the α single-phase region, the thickness of intergranular proeutectoid ferrite increases with rising temperature, leading to reduced hot ductility; (II) In the γ single-phase region, the average size of precipitates increases while the number density decreases with increasing temperature, thereby improving hot ductility; (III) In the α + γ two-phase region, the precipitation of proeutectoid ferrite promotes crack propagation, and the dense distribution of precipitates at grain boundaries causes stress concentration, further deteriorating hot ductility. Heat treatment experiments indicate that under water cooling, air cooling, and furnace cooling conditions, the microstructures of the specimen transform as follows: martensite + proeutectoid ferrite → bainite + ferrite → ferrite; the average size of precipitates first decreases, then increases, and finally decreases again with increasing holding time, while the number density exhibits the opposite trend. Therefore, when the holding time is the same, reducing the cooling rate can increase the average size of precipitates and decrease their number density, thereby improving the hot ductility of 38CrMoAl steel.

Abstract: Among the strategic materials considered by the EU, tungsten is included, thus, investigations about the recovery of this metal both from natural or recycle sources is of interest. In this work we presented an investigation about the recovery of tungsten based on the treatment of three tungsten-bearing concentrates: scheelite, wolframite and a mixed scheelite-wolframite. All of these come from a cassiterite ore of Spanish origin. The characteristics of each concentrate of each concentrate pave the procedure to be followed in each case. In the case of the wolframite concentrate, best results were derived from the leaching of the ore with NaOH solutions, against, the treatment of the scheelite concentrate benefits of an acidic (HCl) leaching. The attack of the mixed concentrate is only possible by a previous roasting step (sodium carbonate and 700-800º C) followed by a leaching step with water. Whereas in the acidic leaching tungstic acid (H2WO4) was obtained, the alkaline-water leaching produces Na2WO4 solutions from which pure synthesized scheelite is precipitated.

Abstract: The paper presents the study results obtained for the reactive interaction and the wetting contact angle when a titanium melt comes into contact with the surface of a calcium ti-tanate substrate. It is shown that the wetting contact angle decreases from 93 to 74° with an increase in the contact temperature of the melt with the CaTiO3 substrate from 1670 to 1728 °C. As the isothermal holding time increases at 1705°C, the wetting contact angle in-creases, and at 1720°C, the wetting contact angle gradually decreases. The processes oc-curring at the interface of the solid and liquid phases are described. It is shown that when titanium comes into contact with CaTiO3, the following processes develop: penetration of titanium melt through capillaries between CaTiO3 particles; dissolution of CaTiO3 in the melt; reduction of calcium to a metallic state and its evaporation with the formation of a vapor layer between the substrate and the melt; diffusion of oxygen into the melt and its binding into a TiO compound that forms a shell on the melt surface. Due to the dissolu-tion of CaTiO3 in the titanium boundary layer and a decrease in the concentration of Ca, a melt is formed after crystallization of which the eutectic CaTiO3+αTi(Ca,O) is formed. The most likely cause of the large wetting contact angle of the CaTiO3 surface by titanium melt is the formation of a vapor layer at the interface between the solid and liquid phases. The found features of the CaTiO3 interaction with titanium melt made it possible to recom-mend it as the basis of molding materials for casting molds intended for the production of castings from titanium alloys.

Abstract: Ferritic stainless steels (FSSs) have attracted considerable attention due to their excellent corrosion resistance and significantly lower cost compared to nikel-bearing austenitic stainless steels. However, the high-temperature wear behavior of additively manufactured FSS 430 has not yet been thoroughly investigated. This study aims to examine the microstructural characteristics and wear properties of laser powder-directed energy deposition (LP-DED) FSS 430 fabricated under varying laser powers and hatch distances. Wear testing was conducted at 25 °C and 300 °C after subjecting the samples to solution heat treating at 815 °C and 980 °C for 1 hour, followed by forced fan cooling. For comparison, an AISI 430 commercial plate was also tested under the same test conditions. Microstructural evolution and worn surfaces were analyzed using SEM-EDS and EBSD techniques. Wear performance was evaluated based on friction coefficients and cross-sectional profiles of wear tracks, including wear volume, maximum depth, and scar width. The average friction coefficients (AFCs) of samples solution heat treated at 980 °C were higher than those treated at 815 °C. Additionally, AFCs increased with hatch distance at both testing temperatures. A strong correlation was observed between Rockwell hardness and wear resistance, indicating that higher hardness generally results in improved wear performance.

Abstract: An effect of temperature and strain rate during the hot rolling process on microstructural evolution in fine-grained Ni3Al intermetallic alloy doped with Zr and B was examined in this work. The hot rolling process was carried out at initial temperature range of 1000, 1100 and 1280C and at the strain rate between 3.9x101 s1 and 2.5 s1. The results of EBSD microstructural analyses revealed that dynamic recrystallization phenomena are initiated at the rolling temperature of 1100C, while a fraction of dynamically recrystallized grains further increases with both rising temperature and strain rate of the deformation process. Furthermore, to estimate heat losses during the hot rolling processing, a non-stationary heat transfer model was formulated and then used to evaluate experimentally received data.

Abstract: In a previous article, an estimation procedure for calculating the liquidus and solidus lines of binary equilibrium phase diagrams was presented. In this article, keeping the thermodynamic basics, the estimation method for the approximate calculation of the liquidus and solidus surfaces of ternary phase diagrams was further developed. It is shown that the procedure has a hierarchical structure, and the ternary functions contain the binary functions. The applicability of the method is checked by calculating the liquidus and solidus surfaces of the Ag-Au-Pd isomorphous ternary equilibrium phase diagram. The application of each level of the developed four-level procedure depends on the data available and the aim. It is shown that in the case of a concentration range close to the base alloy pure element, the liquidus and solidus surfaces of the ternary equilibrium phase diagram can be calculated from the liquidus and solidus functions of the binary equilibrium phase diagrams with a few K errors, which is 0.2 at% at 10 K/at% slope. The equilibrium phase diagrams were available in graphical form, so the data obtained by digitalisation the diagrams for the calculations was used. The functions describe the slope of the surfaces, and the approximate method developed for the calculation of the partition ratios is also shown.

Abstract: The increasing need-based demand of lithium iron phosphate (LFP) batteries in electric vehicles and energy storage systems necessitates the development of efficient and sustainable recycling methods. This study investigates the effect of oxidative roasting on lithium extraction from industrially sourced LiFePO₄ (LFP) blackmass containing high graphite content (~46%) and mixed electrode materials. Roasting at 650°C for one hour converted LiFePO₄ into water-soluble Li₃Fe₂(PO₄)₃ and Fe₂O₃, while reducing carbon and fluorine levels. However, contrary to expectations, mild-acid leaching (pH 2, 40 g/L, 20°C) of roasted blackmass did not improve lithium recovery compared to unroasted material, yielding approximately 33% extraction efficiency. Strong-acid leaching (pH 0, H₂SO₄/H₂O₂) achieved over 95% lithium recovery but also resulted in significant co-dissolution of iron and other impurities. Our XRD and SEM analyses showed that some lithium-containing phases remained in the residue after water leaching, while acid leaching left mainly iron oxide and graphite. These results suggest that, for complex and graphite-rich industrial blackmass, roasting may not always deliver the expected boost in lithium recovery. Our findings highlight the need to tailor recycling processes to the specific characteristics of battery waste and suggest that direct hydrometallurgical methods could be more effective for complex, impurity-rich LFP blackmass streams.